Development of the Dynamic Drive for the new 7 Series of the BMW Group

Abstract

Dynamic Drive is an energy-optimised active roll stabilisation system that will have its first introduction in the new 7 series of the BMW Group. Apart from reducing the roll angle, Dynamic Drive brings about an optimal self-steering effect by a driving condition dependent distribution of the stabilisation torques between front and rear axles. By this means, handling and agility are markedly improved and thus lead to an innovative, but at the same time a BMW typical, Ultimate Driving Machine. Moreover, one experiences a subjective gain in driving safety. As the active stabilizers of the Dynamic Drive, depending on the excitation frequency, introduce slight forces in the body during almost straight-ahead driving, the ride comfort improves - especially in circumstances of asymmetric low-frequency roadway excitation. In this paper, both the system and its two principal components are presented. Then, an insight is given into the methodology of the system development. In this, an extensive comparison is demonstrated between simulation and test results of the Dynamic Drive at a prototype stage; this elucidates the prediction precision of the simulation studies, which had been used for optimisation of the system. In conclusion, the functional evaluation of the Dynamic Drive is discussed on the basis of measured results obtained from the new 7 Series. Apart from quasi-stationary and dynamic driving manoeuvres, a statistical investigation of the interaction between handling and Dynamic Drive is reviewed.